P0sixninja has announced that the Chronic Dev-Team will update their Greenpois0n jailbreak utility within a few days.
GreenPois0n should be updated to support 4.2.1 (tethered or semitethered) within a few days.
According to a recent post by the iPhone Dev-Team, an untethered jailbreak is currently available to only the iPhone3G, older iPhone3GS, and non-MC iPod touch 2G users. @comex is working hard on a method that may untether the 4.2.1 jailbreak for other devices but it will require you to have your 4.1 SHSH blobs in order to use it.
So until and unless Comex of Spirit and JailbreakMe fame comes up with another untethered hack for target=”_blank”>iOS 4.2.1, the jailbreak we get for the newer devices will be tethered (or semi-tethered).
iPhone Jailbreak coverage: